The present invention relates, in general, to a play-free radial ball bearing, and more particularly to a play-free radial ball bearing for steering columns of motor vehicles.
German Pat. No. DE 41 08 827 C2 describes a play-free ball bearing having two outer bearing rings disposed in axial spaced-apart relationship and forming a common outer raceway. The freedom of play is realized through provision of a corrugated spring which extends between a radially inwardly directed flange of an outer sleeve and one of the outer bearing rings. Outer bearing rings and spring element are held together by the outer sleeve to establish a captivated unitary structure, whereby the outer sleeve surrounds the outer bearing rings and spring element on both sides with a respective radially inwardly directed flange.
German Pat. No. DE 41 14 643 C2 describes a roller bearing with an outer bearing ring comprised of two ring portions, which form the outer raceway. Radially inwardly directed flanges on both sides of an outer sleeve respectively surround both ring portions including the corrugated spring, to implement the freedom of play.
FIG. 1 shows a longitudinal section of a conventional steering bearing in the form of a radial ball bearing 1 employing an outer sleeve 7 to hold the components of the ball bearing 1 together. The ball bearing 1 has an axis 2 and is configured as a four-point ball bearing, including an inner bearing ring 3, which is designed as a massive ring. Disposed in spaced-apart coaxial relationship to the inner ring 3 is an outer bearing ring 4, which is comprised of two outer ring portions 4.1, 4.2 spaced from one another at formation of a gap therebetween and establishing together the outer raceway for ball members 5. A corrugated spring 6 loads the movable ring portion 4.1 against the ball members 5 and thus against the other ring portion 4.1. The spring bias is hereby so adjusted as to prevent excessive friction moment in the bearing 1 while ensuring the absence of resilience in axial direction when the steering wheel is under load. The outer sleeve 7, which holds the components of the bearing 1 together, has two radially inwardly directed flanges 7.1, 7.2 to embrace the immobile ring portion 41 and axially ring portion 4.2 of the outer ring 4. This type of bearing is complicated because the outer sleeve 7 has to be bent to form the flanges 7.1, 7.2, and in addition no tolerance compensation between a receiving bore in the housing and the outer surface area of the sleeve 7 is possible.
German Pat. No. DE 43 93 663 C1 describes a radial ball bearing, which includes a spring element in the form of a ring of polymeric material to implement the freedom of play.
For a number of reasons, the various proposals of conventional radial ball bearings are endowed with drawbacks and shortcomings relating for example to complicated manufacturing techniques or to the effect that is hoped to be obtained but may not always be realized. All proposals involve the use of an outer sleeve with radially inwardly directed flanges to hold together the outer bearing rings with the pertaining spring element in order to form a unitary structure. This, however, is very complex. Also, tolerance compensation between receiving housing and outer sleeve is effectively excluded, and the spring element is not protected against overstress.
It would therefore be desirable and advantageous to provide an improved play-free radial bearing which obviates prior art shortcomings and which is easy to manufacture and to assemble which still being reliable in operation and allowing a tolerance compensation with the receiving bearing housing.